1. Technical Field
An encapsulated light-emitting diode device is disclosed.
2. Description of the Related Art
Generally, light-emitting diode chips (LEDs) having transparent substrates are divided into face-up type and flip-chip type. For the face-up type, the light-emitting diode chips are attached to carriers by gels or metals; for flip-chip type, the light-emitting diode chips are attached to carriers by metals or solders with the attached surface as the light extraction surface of the light-emitting diode chip or the surface parallel to it. Because the light extracted from the light-emitting layer of the light-emitting diode chips are 360 degree, the light emitting downward is generally reflected to the front of the light extraction side by the reflecting layers or extracted from the transparent substrates. The thickness of the transparent substrate should be properly adjusted so that the brightness of the light extraction is acceptable. Besides, when the size of the light-emitting diode chips is larger, there are more reflected light passing through the multi-quantum well (MQW) in the light-emitting layer. The light efficiency is reduced because of light absorption.
FIG. 1 shows a schematic illustration of conventional light-emitting device. As shown in FIG. 1, a light-emitting diode chip 100 is attached to a carrier 3 with an attached surface 1 which is parallel to the front light extraction surface 4 of the light-emitting diode chip 100. The light emitted downward is reflected to the front light extraction surface 4 or the lateral light extraction surface 5 by the reflector 2. The disadvantage of this device is when the size of the light-emitting diode chip is larger, there are more reflected light passing through the multi-quantum well (MQW) in the light-emitting layer. The light efficiency is reduced because of light absorption.